The goal of the work proposed here is the evaluation and further development of a unified instrumentation system for clinical vestibular testing. A microprocessor based instrument for the generation of vestibular stimuli and the collection of and analysis of nystagmus type eye movements has been developed during the last three years. Several copies of this device will be evaluated at vestibular testing. Evaluation data will also be used to form an initial, consistent data base of normal and abnormal vestibular responses. Work will continue on two promising vestibular tests which might be later incorporated into the test battery: vertical oscillation testing of the otoliths and caloric testing in the presence of whole body tilts. A portable recorder, monitoring nystagmus as well as EEG and EKG, will be developed for diagnosis of patients with ictal episodes of dizziness.